JPH04160762A - Sealed type lead storage battery - Google Patents

Abstract

PURPOSE:To improve discharge performance by impregnating dilute sulfuric acid in an acid resistant inorganic fine particle packed part, impregnating a sulfuric-acid-containing gel in the upper part in which acid resistant inorganic fine particles are packed, and moreover arranging the sulfuric-acid-containing gel in the upper part space of the said upper part. CONSTITUTION:Acid resistant inorganic fine particles 7, having a mean particle diameter of 10-300mum, are charged and arranged between plates 4 and 5 and in the periphery of a plate group, dilute sulfuric acid is impregnated in an acid resistant inorganic fine particle filled part, a sulfuric-acid-containing gel 10 is impregnated in an upper part in which the acid resistant inorganic fine particles are packed, and moreover the sulfuric-acid-containing gel 10 is arranged in the upper part space of the said upper part. In this case, capacity is increased because the gel 10, delaying the diffusion of sulfuric acid, is used in only the upper part. Moreover such a thing, that a gap in produced in a silica packed part by impregnating and arranging the gel 10 in a silica packed upper part and its upper space, is eliminated. This can improve discharge performance.

Description

[Detailed description of the invention] Industrial applications The present invention relates to improvements in sealed lead-acid batteries.

Conventional technology and its problems There are two types of sealed lead-acid batteries in which the negative electrode plate absorbs oxygen gas generated during charging of the battery: a retainer type and a gel type. In the retainer type, a porous mat separator (glass separator) made of fine glass m fibers with an average pore diameter of around 10 μm is inserted between the positive electrode plate and the negative electrode plate, and this allows the sulfuric acid electrolyte necessary for discharge to flow. It absorbs, retains, and isolates polarities, and in recent years it has become widely used as a backup power source for portable devices and computers. However, the glass separator of the retainer type is expensive, which is an obstacle to the widespread use of this type of sealed battery.

On the other hand, in the gel type, silica sol and dilute sulfuric acid are mixed to form a gel, the sulfuric acid B electrolyte is immobilized, and a mat-like separator (glass separator) is added to reinforce the gel and prevent the positive electrode active material from falling off. I am using it. This glass separator uses a glass separator with an average pore diameter of about 50 μm, which may have a lower ability to absorb sulfuric acid electrolyte than that used in a retainer type. Since such a glass separator is relatively inexpensive, the gel type is cheaper than the retainer type, but such a glass separator has a lower porosity and therefore less electrolyte is contained between the electrode plates.

Therefore, the discharge capacity of the battery was inferior to that of the open type or retainer type.

Furthermore, a sealed battery as disclosed in Japanese Patent Application Laid-open No. 2-158062 is disclosed in which inorganic powder is arranged around an element to absorb and retain an electrolyte. In this case, inorganic powder is inexpensive and has better discharge capacity than the retainer type. However, the problem with this method is that it takes time to inject the electrolyte, and when charging the battery for the first time,
The inorganic powder may blow up due to the gas generated at the end of charging, creating a gas pocket inside the electrolyte holder, resulting in poor contact between the electrode plates and the electrolyte holder, resulting in poor discharge performance. When charging at 0.005 CA, the above-mentioned gas pockets that affect discharge performance are not formed, which is good, or charging takes about 100 hours. Therefore, it is necessary to press this inorganic powder with a porous material so that it does not move, which further increases material costs and process costs.

Means for Solving the Problems The present invention eliminates the above-mentioned drawbacks of the conventional sealed lead-acid batteries and provides an inexpensive sealed lead-acid battery with excellent discharge performance. Acid-resistant inorganic powder with an average particle size of 10 to 300 μl is filled and arranged between the electrode plates and around the electrode plate group, and the acid-resistant inorganic powder filled part is impregnated with dilute sulfuric acid, and the acid-resistant inorganic powder is By impregnating the upper part filled with the body with sulfuric acid-containing gel and further arranging the sulfuric acid-containing gel in the upper space, this acid-resistant inorganic powder is fixed with the sulfuric acid-containing silica gel, and the amount of acid-resistant inorganic powder is This is achieved by minimizing the amount of sulfuric acid required and increasing the total amount of sulfuric acid. The present invention will be explained below based on examples.

EXAMPLE Using three positive electrode plates and four negative electrode plates which were formed by filling a lead alloy grid with ordinary positive and negative electrode pastes, a spacer was inserted between the two electrode plates to produce the electrode plate group shown in FIG. 1. To explain the spacer used here, Fig. 2 is a perspective view of the spacer 1, and the isolation rod 2 made of polypropylene.
are connected at their upper and lower parts by joints 3 and 3', the height h of this spacer being greater than the height of the electrode plate. 4 is a positive electrode plate, 5 is a negative electrode plate, 6 is a battery case, 7
is silica powder, and 8 is an exhaust valve.

Next, after inserting this electrode plate group into a battery case, the primary particle diameter is approximately 30 nn, and the secondary or tertiary average particle diameter is approximately 1100).
1r of silica powder was filled between the electrode plates and around the electrode plate group, and placed up to a height h'. Then SP, GR,1,
30 (20°C) diluted FJAFi was injected to the height of the silica powder, and the silica powder was pressed down from above with foamed phenol having porous open cells as shown in Figure 3. Battery B was manufactured by pouring dilute sulfuric acid, and battery C was manufactured by adding colloidal silica sol to the dilute sulfuric acid so that the silica content was 5 wt %, and pouring the liquid to the height of the upper space H. Then, dilute sulfuric acid is impregnated to the height h' shown in Fig. 1, and a sulfuric acid-containing sol with a silica content of 5 wt% is poured onto the top of the sulfuric acid to the height H, and it is gelled in the battery. A battery according to the present invention was manufactured. For comparison, we made a conventional retainer type battery and a gel type battery, and created Battery E.

It was set as F. Using these batteries, an initial capacity test (51
1R) and charge/discharge cycle test (discharge 0.25C^×
2h, charge Q, ICA x6h, 0.
The battery was discharged at 25CA until the final voltage reached 1.7cm, and the life was determined to have expired when the discharge capacity reached 50% of the initial capacity. ) to compare the performance of each battery. The results of the initial capacity test are shown in Table 1, and the results of the life test are shown in FIG.

As is clear from Table 1, the battery according to the present invention had better discharge capacity than batteries A, B, and C.

The reason why the capacity of battery A was inferior to that of battery cell is that in battery A, gas generated from the electrode plates caused gas accumulation in the silica powder. The reason for the inferior capacity of battery B is
This is because the sulfuric acid content present in the foamed phenol (porous material) intercalable battery was reduced compared to battery D. Furthermore, the reason why the capacity of battery C was inferior was due to poor diffusion of sulfuric acid. The battery cell according to the present invention has the same amount of sulfuric acid as Battery C, and the gel, which slows down the diffusion of sulfuric acid, is used only in the upper part, so it is thought that the capacity increased. Furthermore, by impregnating and disposing the gel only in the silica-filled upper part and the space above it, no voids were created in the silica-filled part, and the same effect as when pressing with foamed phenol was obtained. The reason why the capacity of the battery was superior to that of battery E is as follows. The silica powder is placed all around the plates, whereas the glass separator is present only between the plates. This is probably because the total amount of sulfuric acid held by each was greater when silica powder was used. The reason why the capacity of battery F is small is that the total amount of sulfuric acid is small because the concentration of sulfuric acid injected is low. The reason why the g-acid concentration is lowered in conventional gel-type batteries is that unless the sulfuric acid concentration is lowered by a few percent compared to the retainer type, the life performance will be significantly inferior. Next, the life performance will be explained. Fourth
The life test results are shown in the figure.Batteries A and B had a short life due to their small capacity, and battery C also had a short life because the entire silica powder filling group was impregnated with gel. In this battery, the positive electrode plate deteriorated significantly, and this is thought to be because the use of gel impedes the diffusion of sulfuric acid produced at the end of charging, resulting in a high sulfuric acid concentration near the active material. Furthermore, it had a longer life than the conventional retainer type battery E and gel type battery F.

From these results, battery D of the present invention had the longest life and was excellent.

Furthermore, the average particle diameter of the acid-resistant inorganic powder is 10. If it is less than +tl, it will be difficult to fill, and if it is more than 300 μl, the capacity will be significantly inferior. Therefore, it is preferable to use powder with a volume of 0 to 300 μl. Furthermore, when the distance between the electrode plates is small, a separator is used to prevent short circuits, but it goes without saying that the above-mentioned effects are not impaired in any way even in this case.

Effects of the Invention As is clear from the examples described in 1, the sealed lead-acid battery according to the present invention is cheaper than the conventional sealed lead-acid battery, and furthermore, the discharge performance of the conventional sealed lead-acid battery can be significantly improved. The industrial value is very large.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the sealed lead-acid battery of the present invention, Figure 2 is a perspective view of a spacer, Figure 3 is a cross-sectional view of a sealed lead-acid battery whose top is pressed with foamed phenol, and Figure 4 shows the life test results. FIG. DESCRIPTION OF SYMBOLS 1... Spacer, 2... Isolation rod, 4... Positive electrode plate, 5... Negative electrode plate, 6... Battery container, 7... Silica powder, 9... Foamed phenol, 10 ...Gel'Wl
Figure λ 7 Drunkenness

Claims (1)

[Claims] 1. Fill and arrange acid-resistant inorganic powder with an average particle size of 10 to 300 μm between the electrode plates and around the electrode plate group, impregnate the portion filled with the acid-resistant inorganic powder with dilute sulfuric acid, and A sealed device in which the upper part filled with powder is impregnated with a sulfuric acid-containing gel, and the sulfuric acid-containing gel is further placed in the upper space, and the negative electrode plate absorbs oxygen gas generated during charging of the battery. type lead acid battery.